Decanter centrifuges are used to extract (dewater) solid materials
from liquids when they are mixed together in slurry. Decanter
centrifuges are used in many industrial applications such as:1. Oil /solids separation (oil well drilling, refining,
de-watering)2. Industrial and biological wastewater treatment3. Food processing (olive oil, wine, fruit juice)4. Fish processing (fish meal, fish oil)5. Chemical slurryA main drive motor supplies power to turn the centrifuge. AC drives
are commonly used to power the main drive motor. There are several
different types of decanter centrifuges, such as: Vertical,
horizontal, or scroll (conveyor).

Application Challenges

· Minimize the need for gears or belts to drive the centrifuge.

· Control and maintain speed during the decanting process

· Develop high torque at very low speeds.

· Two motor applications, one for the bowl and one for the scroll.

· The bowl has a very high-reflected inertia.

· The scroll is usually in continuous regeneration, as it runs at a
slower speed than the bowl and is pulled along.

· Dynamic braking or regenerative modules may be required if the
bowl is NOT driven by a drive.

Features of G7 series matching decanter centrifuge application

Features

Benefits

Frequency DetectionSpeed Agree

Both Frequency Detection and Speed Agree signals can interlock with
primary and auxiliary machinery as well as safety equipment while
the machine is operating.

Overtorque or Undertorque Detection

It is possible to notify the user of an impending fault before it
occurs based on the Overtorque or Undertorque Detection settings.

Multi-Step Frequency Reference

Analog inputs are not required due to 17 possible Multi-Step
Speeds. Operating speed can be adjusted for optimum performance.

Dwell Function

Stall Prevention

Feed Forward Function

For accelerating high inertia loads, the user can increase the
Dwell Function setting and tune Stall Prevention. The Feed Forward
function can also be used to assist in acceleration.

DC Injection Braking

High Slip Braking

Although the stop time is generally long due to a large inertia
moment, it is still possible to quickly stop the drive without a
braking resistor by using the DC Braking or the High Slip Braking
function.

Accel/Decel Times

Intelligent Stall Prevention

Fast acceleration and deceleration times are possible by adjusting
Accel/Decel times and using Intelligent Stall Prevention. This can
reduce overall process time.

Fault Restart

The drive can automatically start after being shut off by using the
Fault Restart function.

Flux Vector Motor Control

Provides high starting torque and good speed regulation.

Standard Motor Used

Standard NEMA B design motor can be used to eliminate specially
designed motors.

Energy Saving Mode

Energy saving operation can be implemented at full speed during
light loads.

Power range of G7 VFD

Voltage: 400VAC (380VAC – 460VAC)

Power: 22kw/30HP – 1000kw/1250HP

Specification of G7 VFD

Item

Specification

Input frequency

50/60Hz

Output frequency

0-400Hz

Overload current

150% rated current 1min.

Control mode

Close-loop vector control, sensor-less vector control, V/F control

Starting torque

150% 1hz (with PG 0hz)

Control precision

±0.2% (With PG ±0.02%)

Torque precision

±5%

Setting frequency resolution

Digital command 0.01hz; analog command 0.03hz/60hz

Output frequency resolution

0.01Hz

Frequency setting signal

-10V~+10V；0~+10V(20kΩ)；4~20mA

Protection function

Over voltage, under voltage, over load, relay, overheat speed
stall, grounding, instant power cut compensation( within 2 sec for
operation mode. Continue to operate after the power is available),
Charging protection( not to display when the dc voltage of main
circuit is less than 50v)

Enclosure

IP20

Cooling mode

forced air cooling

Vibration

Less than 0.2g for 20hz

Ambient temperature / Humidity

-10 Degrees~+40 Degrees / 20~90%Rh (no condensation)

Tips:

A variable-frequency drive (VFD) is a system for controlling the
rotational speed of an alternating current (AC) electric motor by
controlling the frequency of the electrical power supplied to the
motor. A variable frequency drive is a specific type of
adjustable-speed drive. Variable-frequency drives are also known as
adjustable-frequency drives (AFD), variable-speed drives (VSD), AC
drives, microdrives or inverter drives. Since the voltage is varied
along with frequency, these are sometimes also called VVVF
(variable voltage variable frequency) drives.